Copied & pasted from a TBN post by Muhammed:
We discovered a malicious code insertion that was appearing when users were accessing the site through certain search engines and using Internet Explorer. We've actually encountered this same issue once before, as it's a common automated script attack of popular forums like ours. Google temporarily blocked our pages as a result. The actual script is a click hijacking malware that steals clicks from search engine results.
We removed the code and have requested a review by Google for the block to be removed. Once that goes through, you should be able to access the forum without any issues. Google says it could take up to a day for the review but we're expecting the alerts to be gone within 12 hours.
Sorry for the inconvenience!